A well-known risk  of consuming marijuana is anxiety and paranoia. The reason behind this, however, is not entirely understood by researchers. This is why Sachin Patel, a neuroscientist at Northwestern University, along with a team of researchers, sought to explore this phenomenon further. “From a biological perspective, we really know almost nothing,” Patel stated. The study was recently published in Nature Communications. 

According to the study, when mice were injected with a synthetic cannabinoid with effects similar to those of THC, they experienced a reaction similar to weed-induced paranoia in humans. 

After receiving their doses, the mice were placed in a cage with a petri dish of fox urine, where researchers observed frantic reactions to the presence of predator urine. Whether it was freezing in place or attempting to escape, it was clear that the mice were experiencing a poor reaction to their dosages. Mice that received larger doses experienced heightened reactions. Patel and his team concluded that this was caused by neurons located in the central amygdala — the part of the brain that controls emotional processing; like anxiety, aggression and fear.  

By implanting microscopes in the rodents’ heads, researchers were able to further investigate how brain cells in the central amygdala responded to the presence of a threat. 

“The take-home,” Patel explained, “was that those cells were hyperactive when combining cannabinoids with the stress exposure.” 

Managing anxiety is an issue that can feel omnipresent in American society. According to an annual poll from the American Psychiatric Association (APA), anxiety rates in the United States continue to rise annually. In 2024, 43% of Americans said they felt more anxious than the previous year, compared with 37% of Americans reporting feelings of anxiety in 2023. And while some research points to cannabis as an effective tool for managing stress and anxiety, other research affirms that cannabis use can exacerbate these feelings. 

Although the study found links between cannabis-induced paranoia amongst mice, researchers noted that these findings may be difficult to apply to humans. However, there may still be some relevance.

“The fact we can mimic that behavioral response in animals quite nicely makes me think that the neural data we have has some relevance to what’s probably going on in humans,” Patel noted.